As a result of shortage of energy, solar cells have been known and utilized more commonly and accordingly, fast terminal boxes associated closely with applications of the cells have also been developed. Upon these terminal boxes, many improvements have been made by engineers.
For example, a fast terminal box comprising a casing and a wiring socket contained therein; plural conductive tabs received in the wiring socket; plural wiring terminals connected with the conductive tabs and springs for clamping the wiring terminals is disclosed in China Patent CN03232075.2. The fast terminal box is characterized in a) said casing is constructed of engineer plastic and has two parallel fixed rails positioned on its bottom; b) at least two parallel wiring sockets are formed on the fixed rails respectively, each sockets having a sliding groove at left and right sides thereof for sliding along a respective fixed rail, and each socket having resilient snap hooks on both sides thereof for connecting with the fixed rails; c) at least two wiring terminals coupled to a dismountable wiring plug component are secured at one side of the casing; d) the wiring sockets each are made of engineer plastic and constructed from a left half portion and a right half portion by fastening them together via insertion of an integral pin shaft into a corresponding pin hole; e) an embedding slot is defined in the socket formed of two halves of the wiring socket with an electrically conductive tab securely embedded therein; f) a cover is disposed on and connected to the casing through insertion or screws for hermetically engaging with one end of the casing. One advantage of this terminal box lies in that suitable number of wiring sockets may be combined together according to desire and snap-fitted to the rails for use. This construction however, is complex due to large quantity of parts and high costs.
For overcoming the abovementioned drawbacks, a fast terminal box which is simple in configuration and convenient to be used is designed. For example, such a fast terminal box is disclosed in patent application No. 200520117035X, which includes a casing, a cover, a wiring socket, a plurality of electrically conductive tabs and several wiring terminals. The plural wiring sockets are located at the bottom of the casing in such a manner that these sockets are parallel to each other, and at least two wiring terminals are located laterally on the casing so as to engage the wiring sockets respectively. Each wiring terminal is coupled to a dismountable wiring plug component. Each wiring socket is formed by combing an upper socket body and a lower socket body together via snap-fitting between several integrally formed snap pins and corresponding snap holes. An embedding slot is defined in the lower socket body of the wiring socket, and an electrically conductive tab is firmly embedded into the slot. The electrically conductive tab has two inserting holes formed at its center portion with a snap pin formed on a bottom surface of each insertion hole. Accordingly, a metal inserting member with two resilient snap pins and two inserting holes defined therein is received in the inserting hole of the electrically conductive tab. The fast terminal box is characterized in the lower socket body is directly secured at the bottom surface of the casing, and a snap opening is defined at each lateral surface of the inserting member for securing pins of a diode therein. The fast terminal box is advantageous due to its simple construction, easy manufacture, low cost and convenient utilization.
In summary, conventional terminal boxes suffer from several drawbacks, since they fail to sufficiently consider heat generated during electrical conduction of both the metal connection member and diode. Especially, with increasing of work current in solar cell devices, this kind of heat generation is more significant, which in turn would affect normal operation of the terminal boxes.